When your Microsoft Excel spreadsheet slows to a crawl, you can’t help but notice. It may take longer to open and save your files, longer for Excel to calculate your formulas, and longer for the screen to refresh after entering data, or sorting and formatting the cells. System memory is the other issue that relates to Excel’s slowness.

Slow spreadsheets take longer to manage and, as always, time is money. We’ll show you how to tackle this problem.

When Excel spreadsheets get too big

Excel is capable of creating a very big spreadsheet, but the bigger it gets, the more memory is needed to keep it open on your PC.

In the current version of Excel, each spreadsheet has 1,048,576 rows and 16,384 columns (A1 through XFD1048576). Each cell can hold a maximum of 32,767 characters. I would not advise pushing these limits.

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The number of records (rows), fields (columns), and formulas can slow down performance considerably. Every time you add new records, then press the Enter key—or use features such as Sort, Format cells, or Insert/Delete Columns or Rows—Excel recalculates all those formulas. This can cause a lag time of several seconds or more between each process. Using a lot of graphical elements can also hinder performance.

One solution, and one that I highly recommend, is to keep your spreadsheets small and tight, with fewer fields and, if necessary, fewer records. You can accomplish this by creating multiple spreadsheets in a single workbook, with links or three-dimensional formulas. You could also create Relational Database spreadsheets that connect your tables with unique, key fields.

Turn on Manual Calculation and use F9

Another solution is to turn off the Automatic Workbook Calculation option, instead using the Function key F9. When Manual Calculation is selected in the Calculation Options, Excel withholds calculating your formulas until you press F9.

1. Select File > Options > Formulas.

2. In the first section: Calculation Options under Workbook Calculation, click the Manual button.

3. Check the Recalculate Workbook Before Saving box if you want to ensure that the spreadsheet calculation is always current. Or uncheck this box if you plan to calculate the spreadsheet manually using the F9 key before exiting.

5. When finished, click OK.

PC World / JD Sartain

Turn off the Automatic Workbook Calculation option to help your sluggish spreadsheet.

Excel memory limits

Users constantly ask me: Why does my spreadsheet say “Excel cannot complete this task with available resources. Choose less data or close other applications?” Similar errors include “Not enough System Resources to Display Completely,” or “There isn’t enough memory to complete this action. Try using less data or closing other applications,” or just “Out of Memory.”

Although memory does not affect Excel’s calculation or manipulation speed, the size of your database (number of columns and rows used) is affected by the amount of available RAM in your system. Remember, just because your computer has 8GB of RAM, that doesn’t mean you have that much available to work with.

PC World / JD Sartain

Excel's memory error message

Excel has its own memory manager and memory limits. The 32-bit version has a limit of 2GB of virtual memory, while the 64-bit version offers up to 8TB of virtual memory. Contrary to some rumors, those numbers include the software itself, plus any add-in programs you have installed.

And that’s just in Excel. Other demands on your system’s memory include the OS, all the other applications that are currently open on your computer, plus a dozen other hidden processes such as DLLs, drivers, and a long list of .exe (executables) that are running in resident memory and/or in the background. Graphics, charts, formulas, and features such as the spell checker, sorting, and printing also consume memory.

For the many users still working with the 32-bit version of Excel, if your spreadsheets are less than 2GB and you’re still receiving memory error messages, try closing all other programs that are running (including the Internet and your email program) to gain additional working memory.

When it's time to move from 32-bit to 64-bit Excel

If the performance and memory tips above both fail to increase your system’s performance or reduce the number of memory errors, then maybe it’s time to switch to the 64-bit version of Excel. This version does not limit your file sizes, but instead enforces limits only by available memory and system resources. This means if your system has 8GB of memory, Excel can access all of that minus whatever the system uses.

If you’re considering a change from Excel 32-bit to Excel 64-bit, here's what to keep in mind:

1. Check out the Large Address Aware update. Microsoft rolled out this patch in June 2016, for 2013 and 2016 Excel versions. This update alters the 2GB limit on address space to 4GB when installed for the 32-bit version of Excel in the 64-bit version of Windows. For 32-bit Excel running in 32-bit Windows, the 2GB address space limit is increased to 3GB.

2. Other files are affected when you install this update: For example, for 32-bit Excel with 32-bit Windows, you must make a change in your boot file. Be sure to read Microsoft’s documentation on the Large Address Aware update before you install anything or make any changes.

3. 64-bit Office only works with 64-bit Windows. You cannot run the 32-bit and 64-bit versions of Office on the same computer. If you attempt this, Microsoft displays an error message.

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You cannot mix 64-bit and 32-bit versions of Office.

4. If you want to upgrade from your 32-bit version to the 64-bit version, you must uninstall and then re-install Office. The reverse is also true.

32-bit vs. 64-bit Excel: Features you'll lose

Despite the performance beneifts of 64-bit Office, Microsoft actually recommends the 32-bit version of Office for most users, because of its greater compatibility with other applications (particularly third-party add-ins). Also, some of Office’s application features are not supported in the 64-bit OS, such as:

1. The legacy versions of Equation Editor and Equation Builder are not supported

2. The Word Add-in libraries are also not supported (many dozens available online for free or for a minimal cost).

3. Some ActiveX controls and some VBA codes are not compatible.

4. Some database files in Microsoft Access have source code issues.

5. Outlook MAPI applications must be recreated, and

6. The Graphics Device Interface (GDI) rendering may have performance issues due to incompatibilities between the 32-bit and 64-bit devices.

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